Powered rope ascenders are gaining use in many industries including industrial access, rescue, and military operations. By using a powered motor attached to a climbing mechanism, they allow users to lift heavy loads along standard lines such as climbing ropes. Powered ascenders are also typically reversible—by reversing the direction of the motor (often after first releasing a safety brake), they can descend lines using the same mechanism as is used to climb. However, the way that powered ascender climbing mechanisms are sometimes constructed can, under some circumstances, impart damage to a rope when the ascender is used to lower a load along a rope. Sometimes a rope will also damage the climbing mechanism.
These drawbacks of using a powered ascender to descend along a rope with a heavy load attached can be magnified when descending along ropes or lines of small diameter. The relatively smaller amount of sheath available covering a 7 mm diameter rope, for instance, will provide reduced protection against the abrasion caused by the climbing mechanism in descent as compared to a larger 11 mm diameter rope whose sheath is proportionally thicker. Much work has gone into climbing mechanisms to increase their efficiency and efficacy while reducing their wear upon the ropes they climb, but fundamentally if they are to function as effectively as they must for climbing purposes, they will provide sub-optimal results when descending, particularly when compared to purpose-built devices for lowering along ropes such as rappelling devices and brake bar racks.
It can therefore be an object of the present invention to provide a device that can be used in conjunction with, or even incorporated into, a powered ascender such that the powered ascender may lower loads along the ropes it climbs and reduce or eliminate the damage the climbing mechanism would otherwise impart on the rope while it descends it. By reducing or eliminating the mechanical wear the ropes experience, the descending device could be said to be assisting the powered ascender in lowering or descent, hence the nomenclature “frictional descent assist device.”
It can be another object of the present invention to provide a device that provides assisted descending functionality along a range of rope diameters including ones smaller than 6 mm in diameter, larger than 11 mm in diameter, and in between.
Other objects and advantages of the present invention will be apparent to one of ordinary skill in the art in light of the ensuing description of the present invention. One or more of these objectives may include:                (a) to provide a device that can be used in conjunction with or affixed to a powered ascender to improve its ability to descend ropes with minimized or no damage        (b) to provide a device that can assist a powered ascender in lowering a heavy load along a rope with minimized or no damage        (c) to provide a device that can impart a frictional drag or braking force to tensile elongate members such as ropes        (d) to provide a device into which a rope can be installed on a bight, without threading a free end through it        (e) to provide a device whose frictional drag or braking force on ropes can be modulated.        